1. Field of the Invention
The present invention relates to a display panel, a method of fabricating the display panel, a method of driving the display panel, a method of correcting a defect in the display panel, and a display employing the display panel.
2. Description of the Related Art
Twisted nematic (TN) liquid crystals making use of the optical rotation of a liquid crystal have presently been employed in available projection displays (liquid crystal projectors) and view finders.
The TN liquid crystal display panel employing the TN liquid crystal needs to employ a polarizing plate to modulate light.
Conventional units such as the aforementioned, however, have poor light utilization efficiency, because the polarizing plate absorbs approximately 70% of incident light. For this reason, the TN liquid crystal display panel has the problem that high brightness display cannot be realized.
The TN liquid crystal display panel also needs a rubbing process, because there is a need to orient liquid crystal molecules. The conventional rubbing process, however, will easily cause a manufacturing defect because it needs high technology. For this reason, there is a problem of panel cost being increased.
The objective of the present invention is to provide a display panel, a method of fabricating the display panel, a method of driving the display panel, a method of correcting a defect in the display panel, and a display employing the display panel in consideration of the conventional problems mentioned.
The first liquid crystal display panel of the present invention comprises, for example, a first electrode substrate (11), a second electrode substrate (12), a liquid crystal layer (21) interposed between said first electrode substrate (11) and said second electrode substrate (12) for forming an optical image as the change of a light scattering state, and a plurality of wires (17) formed on at least one or the other of said first electrode substrate (11) and second electrode substrate (12), wherein the liquid crystal molecules (20) in said liquid crystal layer are oriented by an electric field (19) produced between said wires adjacent on the same substrate.
Also, for example, a polarizing plate (131) is arranged on either the incident side or exit side of the liquid crystal display panel (22) or on both sides. An electric force line (19) is produced parallel to the substrate by the aforementioned adjacent wires (called a transverse electric field wire) (17). Along this electric force line (19), the liquid crystal molecules (20) are oriented. If the liquid crystal molecules (20) are oriented, polarization dependency will occur in a specific direction. If the specific direction is aligned with the polarization axis (132) of the polarizing plate, a scattering characteristic will be enhanced.
In the second display panel of the present invention, a liquid crystal layer (21) and a counter electrode (25), for example, are formed. Then, a color filter (151) is filter directly on the counter electrode (25). Irradiation of ultraviolet rays is performed after formation of the counter electrode (25) and before formation of the color filter (151). As an example of the color filter, there is an interference filter consisting of a dielectric multilayer film and a filter colored with gelatin. Also, the color filter (151) is formed with a protective film (153) for preventing mechanical rapture.
In the third display panel of the present invention, a color filter (151) and a black matrix as a light shielding film (202), for example, is formed on an array substrate (12) and then, on the color filter (151) a thin film (201) having a smoothing and insulating function is formed. On m, this thin film (201), a TFT (155) and a signal line (15), etc. are formed. Thereafter, a counter substrate (11) formed with a counter electrode (25) and the array substrate (12) are held with a predetermined space and then, the space is filled with a mixed solution (315) containing liquid crystal and resin. The phase separation of the mixed solution (315) is performed by irradiating ultraviolet rays from the side of the counter substrate (11).
In the fourth display panel of the present invention, a color filter (151) is not formed on a counter electrode (25). The color filter (151) is formed on another substrate (351). The substrate (351) and the counter electrode (25) are held with a predetermined space by beads (161). The space is filled with an inert gas (352), etc., and the peripheral portion is sealed with seal resin (361) for preventing leakage of said gas.
In the fifth display panel of the present invention, a substrate (11), formed with a color filter (151) and a counter electrode (25), is pasted on a PD liquid crystal layer (21) by an adhesive layer (371). It is preferable that the adhesive layer (371) employ the same material as the resin of the liquid crystal layer (21).
In the sixth display panel of the invention, a counter substrate (11), for example, is thinned, and on the counter substrate (11) a color flter (151) is formed. The relation between the thickness t of the counter substrate (11) and the diagonal length d of a pixel needs to meet the following equation. The color filter (151) is formed after ultraviolet rays are irradiated on the liquid crystal layer (21).
10dxe2x89xa7txe2x80x83xe2x80x83[expression 13]
In the seventh display panel of the present invention, a first PD liquid crystal layer is formed between a pixel electrode (14) and a common electrode (212), and a second PD liquid crystal layer is formed between the pixel electrode (14) and a counter electrode (25). If voltage is applied to the pixel electrode, the first and second PD liquid crystal layers will be caused to be in a light transmitting state at the same time. Since the sheet resistance value of the common electrode (212) is reduced, a metal wire (471) is formed along the common electrode (212).
A light shielding film 542 is formed above or below a driver circuit (541), etc. which drives the display panel of the present invention. The light shielding film (542) shuts out light that is incident on the driver circuit (541). Or, instead of the light shielding film (542), the driver circuit (541) is enclosed with a light absorbing resin (541).
In the eighth display panel of the present invention, for example, a light modulating layer (21) is not formed between pixel electrodes (14), but space is assured. Also, on a signal line (15) a BM (202) is formed. Preferably, an inert gas (352) is injected into the aforementioned space. A fabrication method fabricates a mask 181 having a light shielding film (202) formed so as to correspond to the space between pixel electrodes (14), and irradiates ultraviolet rays (183) through the mask (181). The ultraviolet rays (183) irradiated on the light shielding film (202) is reflected or absorbed. For this reason, the resin under the light shielding film (202) is not set. After irradiation of the ultraviolet rays (183), if the unset resin (315) is washed, space can be formed on a signal line.
In the ninth display panel of the invention, a color filter (151), for example, is formed on a pixel electrode (14). A PD liquid crystal layer (21) varies the average particle diameter of a waterdrop-like liquid crystal or the average pore diameter of a polymer network in accordance with the color of the color filter (151). When the color filter (151) is red (R), the average particle diameter or average pore diameter is increased, and when the color filter (151) is blue (B), the average particle diameter or average pore diameter is reduced. The size of the average particle diameter or average pore diameter is adjusted by varying the strength of ultraviolet rays to be irradiated and/or the kind and content of liquid crystal and resin. Also, as shown in FIG. 28, the size is adjusted by irradiating ultraviolet rays with the use of a transparent substrate (642) formed with microlenses (641) different in focal distance. The microlenses (641) may be replaced with prisms, as shown in FIG. 67.
The tenth display panel of the present invention is constituted, for example, so that the content of the resin component on a pixel electrode (14) is increased and also the content of the liquid crystal component of the peripheral portion of the pixel electrode (14) is increased. The refractive index of a liquid crystal is higher than that of resin. For this reason, in the display panel shown in FIG. 70, the refractive index of the central portion on the pixel becomes lower than that of the peripheral portion of the pixel. Therefore, if the refractive index of the liquid crystal component in a mixed solution (315) is higher than that of the resin component, each pixel will serve as a concave lens.
The eleventh display panel of the present invention is provided, for example, with a microlens array (641). By forming a microlens array substrate (642) and a color filter (151), color display is realized without forming the color filter (151) on a liquid crystal layer (21). Also, the microlenses (641) may be colored red (R), green (G), and blue (B).
The microlens (641) has both the function of a microlens and the function of a color filter (151). The microlens may be replaced with a Fresnel lens.
Also, if the microlens (641) is formed between pixel electrodes (14), the same effect as the BM (202) formed between pixel electrodes (14) can be obtained.
In the twelfth display panel of the present invention, thin film or thick film consisting of resin is formed on the lower layer of a counter electrode or a pixel electrode, and the film thickness of a liquid crystal layer (21) is varied according to the color of the pixel electrode (14). A red pixel is made thicker in film thickness than a blue pixel. Preferably, the average particle diameter of the waterdrop-like liquid crystal of the red pixel is made larger than that of the waterdrop-like liquid crystal of the blue pixel.
In the thirteenth display panel of the present invention, a reflecting surface with irregularities, for example, is formed on one side of the substrate of the display panel. Alternatively, irregularities are formed on a surface (counter electrode 25 or pixel electrode 14) contacting a liquid crystal layer, and a color filter (151) is formed on the irregular surface.
In the fourteenth display panel of the present invention, a pixel electrode (14) is formed from ITO, and on the ITO a dielectric mirror (891) is formed. If voltage is applied to the pixel electrode (14), a liquid crystal layer (21) will be caused to be in a light transmitting state. The correction of a pixel defect is performed by (irradiating) laser light from the dielectric mirror side.
In the microlens of the present invention, a microlens array is formed, for example, by forming on a substrate a thin film pattern which becomes a core, coating a resin solution on the substrate, and by setting the resin solution. A microlens array substrate with concave or convex lenses can be formed according to the shape of the thin film pattern. Also, a reflection type microlens array can be fabricated by forming thin metal film on the aforementioned microlenses.
To narrow the directivity of light emerging from the display panel of the present invention, a microlens array or a prism sheet is arranged on a light reflecting surface or the light exit surface of the display panel. Also, a light guiding plate is arranged on the light incidence surface of the display panel.
The display panel of a fifteenth invention is constituted, for example, so that current flows through a counter electrode (25). Wires (1693) are formed on both ends of the counter electrode (25), and if a switch (1692) is closed, current will flow between wires (1693a) and (1693b). When current flows through the counter electrode (25), it is converted to heat and then, a liquid crystal layer (21) is heated and the temperature of the liquid crystal layer is raised to a predetermined value.
The driver circuit of the display panel of the present invention is constituted, for example, by transistors formed with a high-temperature polysilicon technique, a single crystal polysilicon technique, or a low-temperature polysilicon technique. Inverters of multiple stages are connected to the output of the shift register of the driver circuit. The output of the inverter of the last stage is connected to the gate of an analog switch. The analog switch outputs a video signal to a source signal line (15).
The display panel of the present invention needs to meet the following relation:                               10          ⁢          D                ≤                  W          L                ≤                  50          ⁢          D                                    [                  expression          ⁢                      xe2x80x83                    ⁢          14                ]            
where W is the width of the gate of a transistor constituting an inverter, L is the length of the gate, and D is the diagonal length of a display area on the liquid crystal display panel.
Also, the display panel needs to meet the following relation:                                           200            ⁢            D                                μ            ⁢                          xe2x80x83                        ⁢            p                          ≤                  W          L                ≤                              1200            ⁢            D                                μ            ⁢                          xe2x80x83                        ⁢            p                                              [                  expression          ⁢                      xe2x80x83                    ⁢          15                ]            
where xcexcp (cm2/V*sec) is the mobility of the P-channel transistor.
In addition, the display panel needs to meet the following relation:
0.25 less than (Wnxe2x88x921/Lnxe2x88x921)/(Wn/Ln) less than 0.75xe2x80x83xe2x80x83[expression 16]
where Wnxe2x88x921 is the length of the gate of the (nxe2x88x921) st inverter, Lnxe2x88x921 is the length of the gate, Wn is the width of the gate of the nth inverter of the next stage, and Ln is the length of the gate.
Furthermore, the relation between the power source voltage V1 for the inverter connected to the gate of the analog switch (1192) and the power source voltage V2 for outputting a logic signal to the signal input terminal of the inverter needs to meet the following equation. Note that the power voltage for the shift register is V2.
V2 less than V1xe2x80x83xe2x80x83[expression 17]
In the display panel of a fifteenth invention, a concave lens-shaped or plate-shaped transparent substrate is mounted on a light incidence surface or light exit surface. The transparent substrate has a radiating plate mounted thereon. Also, the transparent substrate is filled with liquid or gel.
In the sixteenth display panel of the present invention, four color pixels, for example red(R), green(G), blue(B), and brightness (W) pixel are arranged in the form of a mosaic. For the pixels, signals different in polarity for each frame are written.
The defect correction method of the present invention is, for example, a defect correction method for a polymer dispersion liquid crystal display panel. In this method, laser light is irradiated on the liquid crystal layer (21) of the liquid crystal display panel to change the quality of the liquid crystal layer (21).
The defect correction apparatus of the present invention is, for examle, a defect correct apparatus for display panel which comprises observation means for detecting at least either the position of the pixel electrode (14) of a display panel or the position of the switching element (155) by infrared rays, laser light irradiation means (901) for irradiating laser light, and positioning means (911) for positioning the liquid crystal panel so that the position detected by the observation means (902) and the position at which the laser light is irradiated are superimposed with each other.
The display according to the present invention is, for example, provided with video signal processing means for computing an average amplitude value from a video signal during a video signal period in one horizontal period and then computing a first voltage from the computed average amplitude value and source signal application means for applying the first voltage to a plurality of source signal lines during a blacking period in one horizontal period.
In the first display panel drive method of the present invention, for example, an average amplitude value is computed from a video signal period in one horizontal period. Then, voltage is computed from the computed average amplitude value. The computed voltage is applied during a horizontal blanking period so that each pixel of the liquid crystal display panel has a desired transmittance.
In the second display panel drive method of the present invention, for example, the polarity of a video signal which is applied to a counter electrode (25) is inverted for each horizontal scanning period. Then, a video signal is applied from a source driver circuit (491) to a source signal line (15) with the potential of said counter electrode (21) as reference, and also the polarity of said video signal is inverted for each horizontal scanning period.
In the third display panel drive method of the present invention, for example, a video signal is converted to a digital signal and retained in memory as data. Then, the retained data is read out at a double speed and written by the display panel. In the remaining half frame (or half field) period, black display is written to the display panel at the same double speed. In other words, this method performs black displayxe2x86x92image displayxe2x86x92black displayxe2x86x92image display in the recited order.
In the fourth display panel drive method of the present invention, for example, a display panel is arranged within a cylindrical light shielding member formed with slits, and an image on the display panel is gradually shut out from the upper portion of the screen.
The first display panel fabrication apparatus of the present invention is, for example, constituted so that a mixed solution (315) is, supplied to the space between a separation film 182 and a substrate (12) and pressed by a press roller (312). Ultraviolet rays (183) is supplied in the form of lines to the mixed solution 315. After phase separation of the mixed solution, the separation film (182) is wound up by a wind-up roller (314).
The second display panel fabrication apparatus of the present invention is provided, for example, with a mounting table for placing a display panel (22). The mounting table has a heater (739) for heating the panel (22) to a predetermined temperature. Liquid or gel (735) is supplied to the space between a diffusing plate (734) and the display panel (22) through a supply tube (732). The peripheral portion is sealed by seal rubber (736) so that liquid or gel does not leak. Ultraviolet rays (183) are irradiated on the display panel (22) through the light diffusing plate (734). The ultraviolet rays (183) are scattered by the diffusing plate (734) and are irradiated evenly on the entire mixed solution of the display panel.
The third display panel fabrication apparatus of the present invention is constituted, for example, so that ultraviolet rays can be irradiated from the back surface of a display panel (22). The mixed solution of the display panel (22) can be heated to a predetermined temperature by the infrared rays. On the front surface of the display panel (22) an infrared-ray reflecting plate (741) is arranged. The reflecting plate (741) reflects the infrared rays transmitted through the display panel (22) and heats a mixed solution (315) from the front surface of the display panel (22) as well. Liquid or gel (735) is supplied to the space between a diffusing plate (734) and the display panel (22) by a supply tube (732). Ultraviolet rays (183) are irradiated from the side of a counter electrode (25) formed on the front surface of the display panel (22) onto the mixed solution (315) through the diffusing plate (734). On the back surface of the display panel (22) an ultraviolet ray reflecting plate (742) is arranged. The reflecting plate (742) reflects ultraviolet rays (183) and accelerates the phase separation of the mixed solution from the back surface of the display panel as well.
In the fourth display panel fabrication apparatus of the present invention, a display panel (22) is housed within a casing (742) and the periphery of the display panel (22) is filled with liquid or gel (735). On the interior surface of the casing (742) a reflecting plate (742) is formed, and the reflecting plate reflects the ultraviolet rays (183) irradiated through a diffusing plate (734). For this reason, ultraviolet rays (183) are irregularly reflected within the casing (742), and consequently, ultraviolet rays are irradiated from the entire circumference of the display panel (22) on a mixed solution (315).
The first projection type display of the present invention is provided, for example, with a discharge light emitting lamp, a liquid crystal display panel, secondary-illuminant formation means for focusing light emitted from the discharge light emitting lamp to form a secondary illuminant, a projection lens for projecting an optical image formed by the liquid crystal display panel, first lens aperture means arranged on a light incidence side of said liquid crystal display panel, and second lens aperture means arranged on a light exit side of said liquid crystal display panel.
The relation with the effective F number F of the projection lens needs to meet the following equation:                                                         3              ⁢              DG                                      2              ⁢              L                                ≤          F          ≤                                    4              ⁢              DG                        L                          ⁢                  
                ⁢                  G          =                      π            ⁢                          xe2x80x83                        ⁢                          B              /              E                                                          [                  expression          ⁢                      xe2x80x83                    ⁢          18                ]            
where D (inch) is the diagonal length of the display area of the liquid crystal display panel and L (mm) is the arc length of the discharge light emitting lamp.
In the second projection type display of the present invention, a display panel with color filters in the form of a mosaic is employed as a light valve. On the exit side of a light source (1414) a color purity enhancing filter (1412) for enhancing color purity is arranged. Also, on the exit side of the display panel (22) a polarizing plate (131) is arranged, and the polarizing plate (131) is detachable from an optical axis (1416).
The third projection type display of the present invention is constituted so that an infrared-ray cut filter (1702) is detachable from an optical axis (1416). It is preferable that an infrared-ray absorbing filter (1703) be arranged on the light incidence surface of a display panel (22). In the case of low temperature, the infrared-ray cut filter (1703) is not inserted in the optical axis (1416) immediately after the lamp is lit. For this reason, the display panel (22) is heated by radiation heat and the temperature of the liquid crystal layer (21) is quickly raised. The temperature of the liquid crystal layer (21) is detected by a temperature sensor (745). If the temperature of the liquid crystal layer (21) reaches a predetermined value, the infrared-ray cut filter (1702) will be inserted in the optical axis (1416).
In the fourth projection type display of the present invention, for example, a rotary filter (1414) is arranged in an optical axis (1416). The rotary filter 1414 is formed by bonding a polarizing plate (131) to a substrate. However, the quarter area does not have the polarizing plate (131). The rotary filter (1414) is constituted so that it is rotatable on a rotational center (2023). If the rotary filter (1414) is rotated, the direction of the polarization axis (132) of the transmission range (2022) of light which is projected onto a screen (1501) will be changed. The rotary filter 1414 rotates in synchronization with the vertical synchronizing signal (VS) in a video signal. The rotary filter (1414) is rotated 90xc2x0 for each vertical period. Also, an image for the right eye and an image for the left eye are switched for each frame and displayed on the display panel (22).
In the fifth projection type display of the present invention, for example, at least either the distance between a display panel (22) and a lamp (1411a) or the distance between the display panel (22) and a projection lens (1415) can be contracted. This projection type display is also provided with a mechanism for fine adjustment of lamp position. When the projection type display is carried, the overall length thereof is contracted. When the projection type display is used, the overall length is extended so that an image on the display panel (22) can be projected onto a screen by a projection lens.